Chapter 45: Antineoplastic Agents

Antineoplastic Agents exploration of antineoplastic pharmacology examines the medicinal strategies used to combat cancer, defined as the unregulated proliferation of abnormal cells. The chapter details the biological transformation of healthy tissue into malignancies through genetic mutations that activate oncogenes or disable tumor suppressor genes like p53, often facilitating invasiveness, metastasis, and the formation of new blood supply through angiogenesis. Treatment methodologies are categorized into traditional cytotoxic chemotherapy, targeted small molecule inhibitors, and hormonal therapies. Cytotoxic agents are further classified by their relationship to the cell cycle, with some targeting specific phases such as DNA synthesis in the S phase or mitosis in the M phase, while others, like alkylating agents and platinum compounds, act non-specifically throughout the cycle. Key drug classes discussed include folate antagonists like methotrexate, purine and pyrimidine analogs, nitrogen mustards, and intercalating antibiotics such as doxorubicin, which is noted for its potential cardiotoxicity. The text explains the challenges of clinical oncology, including the log-kill hypothesis for tumor reduction and the emergence of drug resistance through mechanisms like P-glycoprotein efflux pumps. Furthermore, it highlights the shift toward precision medicine with small molecule inhibitors that target specific enzymes like BCR-ABL tyrosine kinase in leukemia or EGFR in lung cancer. The discussion extends to hormonal interventions for gender-specific malignancies, utilizing estrogen antagonists for breast cancer and androgen suppression for prostate cancer. Throughout, the chapter emphasizes the management of significant adverse effects, such as bone marrow suppression, neurotoxicity, and organ-specific damage, providing a vital framework for understanding modern cancer pharmacotherapy.